What is the partial pressure of oxygen $(pO_2)$ in the alveoli of the lungs compared to the blood?

Identify the correct option for the diffusion membrane.

Diffusion of gases occurs in the alveolar region only and not in the other parts of the respiratory system. Why?

What will be the $pO_{2}$ and $pCO_{2}$ in atmospheric air as compared to alveoli?

Given below are two statements.
Statement $I$: Respiratory membrane is composed of two layers of squamous epithelia,each resting on a thick basement membrane.
Statement $II$: The diffusion of a respiratory gas takes place from lower partial pressure to higher partial pressure of the same.
In the light of above statements,choose the most appropriate answer from the options given below:

Maximum amount of oxygen is lost from the blood in the